Hello all, I'm new to the forum and to wheelin. I have a '94 rodeo LS 4wd. Yesterday I went off-roading for the first time and it was GREAT. When I got there I noticed everyone was deflation their tires. I know this is done to increase traction, but I wasnt sure as to how much I was supposed to deflate my tires. I have 265/70r16 yokohama geolanders II's.
when I checked the tire presure before deflating, they were all at about 35, so I took them downt to 30 PSI not wanting to go too low. anyway, I'm not sure if this was the correct PSI, but it seemed to be fine. I went thru rockbed streams, thru sand, rocks and thru thick mud without much problems. I even climbed and decended some steep angles just as well as most. I can honestly say that I am officially hooked to off-roading after yesterdays experience. I just want to get as much info and feedback from you veterans before I seriously get into this. I'm already considering buying the calmini 3' inch suspension lift.
But back to basics, as I'm planning on going back next
Sunday so, what should I set my PSI at?

I take mine down to the 10-14 psi range. As you stated, lower pressure = increased traction. The lower you go, the more chance you have of loosing a bead, though (I've only ever lost one; and it was after cutting a sidewall... so the tire was effectively at 0 psi). A lot of how low you can go has to do with the width of the tire compared to the width of the wheel. A skinnier wheel will help with bead retention versus a wider wheel with the same tire... but you also don't want the wheel too skinny for a DD because it will make the tires crown and cause uneven wear. My OEM's were 31x10.50 on 15x7 wheels and I now run 32x11.50 on 15x8's. The 32x11.50's on my OEM 15x7's crowned a bit much for my liking. Anyway, after a bit of explaning the method behind the madness, I'd say take them down to around 18psi next time and see how you like it. If you are worried about loosing a bead, I wouldn't consider it an issue at that pressure.

On stock wheels a quick rule of thumb is to go down to half of your road psi...you can go even lower with steel wheels.

I like to "break"the tires in.Not sure if it really works but I haven't broke a belt yet.
Since you went to 30# next time take them to 25# and then the next time 20#.I wouldn't go much lower with the 265's because the tire will want to roll around alot.
After 20# you'll loose alot of ground clearance and since each tire/wheel combo is different this will give you a chance to experiment.
Don't drive hard/fast at lower pressures because theres more chance for a rock to deflect into wheel at impact and possible cut the sidewall as the tire get's pinched.
Goodluck and welcome to the board.

Bansil

18 to 20 psi has always worked pretty well for me. <img src="/forums/images/graemlins/kewl.gif" alt="" />



Plus it might scare your passenger half-to-death <img src="/forums/images/graemlins/scared.gif" alt="" /> - especially, say:
Rally/Autocrossing it over a series of side-hills at 30+ mph to catch-up with the rest of the group, along a thoroughly rock-strewn one lane access trail, at about 11 PM at night...

Right, Bansil? <img src="/forums/images/graemlins/evil.gif" alt="" /> <img src="/forums/images/graemlins/lol.gif" alt="" /> <img src="/forums/images/graemlins/lol.gif" alt="" /> <img src="/forums/images/graemlins/lol.gif" alt="" />


<img src="/forums/images/graemlins/cheers.gif" alt="" />
<img src="/forums/images/graemlins/smile.gif" alt="" />

I have a theory. Considering that there are different load ratings and weighted trucks my rule of thumb is to air down till the side wall buldges a bit.

My reasoning for not really speaking in PSI is because with a set of D load tires you will need to air down much more than the same tire with a C load rating. The sidewalls are much stiffer and require more air to be removed to gain the same results.

My two little copper coated metal pieces that cost more to produce than they are worth....

Joe

I take mine down to 10 to 12 pounds.

<img src="/forums/images/graemlins/cheers.gif" alt="" /> <img src="/forums/images/graemlins/kewl.gif" alt="" />

yeehawwwww!!!!! ........ooooooooouch! <img src="/forums/images/graemlins/lol.gif" alt="" />

thanks for all the feedback guys! I think im going to try reducing the PSI to 25 next time and then to 20 the next, like was suggested by bansil...heres to wheelin'! <img src="/forums/images/graemlins/cheers.gif" alt="" />

Seriously? Keep lowering pressure 5psi at a time until you start loosing tire beads... then add pressure to that number 1psi at a time until you stop loosing tire beads... then add a few psi for safety and wheel right on past the 90% of folks out there running WAYYYYyyyyyyyyyyyyyyyy too much pressure.
Only exception -- if you're running smaller tires and can't afford the clearance. If that's the case, get some bigger tires and enough lift or sawzall to fit 'em and then start reading this post again from the top.

Randii